There are a huge range of refrigerators available for Caravans and RV's, but how do you know which one is right for you? Whats the difference between 3-way & 2-way and which is best??

Here we will breakdown the 2 types of fridge available, as well as the pros & cons of each so that you can be confident you are choosing best fridge for you.

1. What's the difference between 3-way and 2-way?

While all fridges use the same principle to provide cooling, there are two different ways that this can be achieved. Basically, cold cannot be created - rather it is the side effect of a lack of heat.
Both methods use the change of state of the refrigerant (Liquid to Gas and back to Liquid) to essentially suck out the heat to provide this cooling effect.

In 3-way or Absorption refrigerators, this change is caused by the cycling of ammonia, water and hydrogen which naturally react together and only require a heat source to maintain the reaction. These fridges can operate on Gas, 12V or 240V. Dometic 3 way fridges have dominated the market for many years, but more recently Thetford have begun to make great in-roads and provide a great alternative.

2-way or Compressor fridges work the same way as your fridge at home. As the name suggests, they must compress the refrigerant vapour back into liquid form to continue the cooling cycle. These fridges operate on electricity only and can be powered by 12V, 24V or 240V. The latest Waeco 12V fridges come standard with a 240V power lead, but Vitrifrigo's require an additional adaptor to operate on 240V.

Different Cooling Systems used in Absorption & Compressor Fridges

2. How Efficient Are 3-way & 2-way Fridges?

For those who prefer free camping to caravan parks, the 3-way fridges offer great efficiency when running on Gas. A good 3-way fridge will be able to last a couple of weeks on a single 9kg gas bottle, so are great for those who like to stay off the grid.

The downside is they are much less efficient than the compressor fridges when running on 12V, so they will chew through your battery quickly if left running on 12V after your car has stopped.
Some 3-way fridges come with AES (Automatic Energy Selection) which will automatically select the best energy source available. For example 12V while the car is running, then switches to Gas once stopped to avoid draining your battery.

Compressor fridges are designed for 12V to be their primary power supply, so are much more efficient when running on 12V than the 3-ways. As efficient as they are, you will still need a good battery / solar setup if you plan on spending time away from mains power.

3. How Well Do 3-way & 2-way Fridges Cool?

The absorption method of cooling used in 3-way fridges is less effective at cooling quickly, and can suffer in high ambient temperatures. Tropically rated 3 way fridges are available in some sizes and will achieve lower temperatures even when outside temperatures are quite high.

Cooling power is where the compressor fridges really shine - they work the same way as your fridge at home and are much better at maintaining the fridge temperature even in high ambient temps. If you are planning on spending a lot of your time travelling in hotter areas, Compressor may be the best option for you.

4. Are 3-way & 2-way Fridges Noisy?

3 way have the advantage of being completely silent, as the absorption cooling method has no moving parts. They do have thermostatically switched fans to increase airflow but these are very quiet.

Compressor fridges are not silent however and the compressor hum can be annoying particularly when it comes time to sleep. While there will be some noise, most quality compressor fridges are still fairly quiet.

5. How Are 3-way & 2-way Fridges Installed?

Another thing to consider is installation. 3-way fridges must be properly vented to the outside of the RV to allow heat and any gas emissions to escape.
They must also be completely sealed from the cabin so no gasses can enter the living area. The vents also help to keep the fridge cooled for maximum performance.

A helpful guide from Dometic about venting requirements can be found here:

Compressor fridges on the other hand are much simpler to install, and do not require any venting.
They will also operate normally if the van is not level, while absorption fridges need to be level to work effectively.

Some 2-way fridges come with a remote compressor, which means instead of being built into the back of your fridge they can be stored nearby instead. This gives you maximum capacity in the fridge as you do not lose a portion of your cabinet to accommodate the compressor.

3 Comments

Ian

Peter

Don Fellows

I have been caravaning for more than 50 years so have had many fridges. For me, compressor fridge with a good solar system are the only way to go. I have had Waeco and now have EvaKool. Waeco, I would not have again, but I love my EvaKool. With due respect, I feel that your comments about the compressor fridges noise when sleeping are not correct. A little deaf I may be, but I have never heard any night noises that could keep anyone awake from either of my compressor fridges, and especially the EvaKool. I feel that your comment is misleading. I do not have any connections with any fridge suppliers and this is unbiased comment. Kindest regards, Don Fellows.